Much of this will depend upon how the grounding connections are made on each of the systems. This problem can often be solved by merely using an inexpensive ground defeater plug, a 3 prong to 2 prong addapter plug that is available in any hardware store for under $2. Just plug the ground defeater into the wall outlet, then plug your powered speaker into the addapter. This may solve your problem with very little expense.

Good Luck,

Gary

------------------
Travlin' Easy
_________________________
PSR-S950, TC Helicon Harmony-M, Digitech VR, Samson Q7, Sennheiser E855, Custom Console, and lots of other silly stuff!

K+E=W (Knowledge Plus Experience = Wisdom.)